WO2018055683A1

WO2018055683A1 - Robot, power transmission device, and power transmission system

Info

Publication number: WO2018055683A1
Application number: PCT/JP2016/077775
Authority: WO
Inventors: 晃司川田; 村松　啓且; 基範川内
Original assignee: ヤマハ発動機株式会社
Priority date: 2016-09-21
Filing date: 2016-09-21
Publication date: 2018-03-29
Also published as: JPWO2018055683A1; JP6719568B2

Abstract

The present invention comprises: a ball screw having a screw shaft; a coupling device having provided therein a first fitting hole and a second fitting hole and being fastened to the screw shaft fitted into the first fitting hole; a motor that rotates an output shaft; and a power transmission device having a first rotating section having a third fitting hole opened therein into which the output shaft can be fitted, a second rotating section having protruding therefrom a protruding shaft that can be fitted into the second fitting hole, and a transmission section that transmits the rotation of the first rotating section to the second rotating section. In a state in which the output shaft and the screw shaft are arranged upon different axes, the coupling device is fixed to the second rotating section as a result of: the output shaft, fitted into the third fitting hole facing one side in the thrust direction, being fixed to the first rotating section by being coupled to the first rotating section; and the protruding shaft being fitted into the second fitting hole and coupled to the coupling device. On the other hand, the coupling device is fixed to the output shaft as a result of the output shaft being fitted into the second fitting hole and coupled to the coupling device, in a state in which the power transmission device is detached from the output shaft and the coupling device and the output shaft and the screw shaft are arranged upon the same axis.

Description

Robot, power transmission device, power transmission system

The present invention relates to a technique for transmitting rotation of a motor output shaft to a screw shaft of a ball screw.

In an industrial robot such as a single-axis robot, a linear motion mechanism is generally used in which a moving body screwed into a ball screw is moved by driving the ball screw with a motor. There are two methods for transmitting the rotation of the output shaft of the motor to the screw shaft of the ball screw. One is a series system in which output shafts arranged in series and screw shafts are coupled by coupling, and the other is an output shaft arranged in parallel as described in Patent Document 1. This is a parallel system that couples the screw shaft. Specifically, the latter system uses a pulley attached to the shaft end of the output shaft, a pulley attached to the shaft end of the screw shaft, and a timing belt spanned over these pulleys, and outputs the output shaft. Is transmitted to the screw shaft.

JP-A-10-235579

By the way, the parallel system can shorten the robot instead of increasing the width of the robot, while the serial system can suppress the width of the robot instead of increasing the length of the robot. In this way, both systems differ in merits and demerits. Therefore, there is a need for a technique that can easily switch between the serial method and the parallel method in accordance with the installation environment of the robot. *

The present invention has been made in view of the above problems, and provides a technique that allows a method of transmitting rotation of the output shaft of a motor to the screw shaft of a ball screw to be easily switched between a series method and a parallel method. With the goal.

A robot according to the present invention includes a ball screw having a rotatable screw shaft, a moving body that is screwed to the screw shaft and moves as the screw shaft rotates, and a first insertion hole that opens to one side in the thrust direction. A second fitting hole that opens to the other side in the thrust direction, and a coupling device fastened to a screw shaft fitted in the first fitting hole, a rotatable output shaft, and the output shaft is rotated. A motor, a first rotating part having a third insertion hole into which the output shaft can be fitted, a second rotating part having a projecting shaft that can be fitted into the second fitting hole, and the rotation of the first rotating part to the second rotation A power transmission device having a transmission portion for transmitting to the portion, and in a state where the output shaft arranged toward the other side in the thrust direction and the screw shaft are arranged on different axes, the one side in the thrust direction is The output shaft fitted in the third insertion hole facing the first The coupling device is fixed to the first rotating portion by being fastened to the rolling portion, and the projection shaft is fitted into the second insertion hole so as to face one side in the thrust direction, and is fastened to the coupling device. While the power transmission device is removed from the output shaft and the coupling device while the output shaft of the motor and the screw shaft are arranged on the same axis while being fixed to the rotating part, the output shaft is fitted into the second insertion hole and coupled. The coupling device is fixed to the output shaft by being fastened to the device.

The power transmission device according to the present invention includes a first rotating portion having a third insertion hole into which a motor output shaft can be inserted, a first insertion hole opening to one side in the thrust direction, and the other side in the thrust direction. A second insertion hole that opens, and is fastened to a screw shaft of a ball screw fitted in the first insertion hole, and is arranged on the same axis as the screw shaft and is fitted on the output shaft fitted in the second insertion hole. A second rotating part having a projecting shaft that can be fitted into the second fitting hole of the coupling device capable of being fastened; and a transmission part for transmitting the rotation of the first rotating part to the second rotating part, on the other side in the thrust direction The output shaft fitted in the third insertion hole facing one side in the thrust direction is fastened to the first rotating portion in a state where the output shaft and the screw shaft arranged in the direction are different from each other. And is fixed to the first rotating part. By projecting shaft toward one side of winding direction is fastened is fitted into the second fitting hole of the coupling device, the coupling device is fixed to the second rotating portion.

The power transmission system according to the present invention includes a first insertion hole that opens to one side in the thrust direction, and a second insertion hole that opens to the other side in the thrust direction, and the ball screw that is fitted into the first insertion hole. A coupling device that can be fastened to the screw shaft; a first rotating portion that has a third insertion hole into which the output shaft of the motor can be fitted; a second rotating portion from which a protruding shaft that can be fitted into the second fitting hole projects; A power transmission device having a transmission portion for transmitting the rotation of the first rotation portion to the second rotation portion, and the output shaft and the screw shaft arranged toward the other side in the thrust direction are arranged on different axes. In this state, the output shaft fitted in the third insertion hole facing one side in the thrust direction is fastened to the first rotating portion, so that the output shaft is fixed to the first rotating portion, and one side in the thrust direction Facing the second insertion hole When the protruding shaft is fastened to the coupling device, the coupling device is fixed to the second rotating part, while the power transmission device is removed from the output shaft and the coupling device, and the output shaft of the motor and the screw shaft are arranged on the same axis. In this state, the output shaft fitted in the second insertion hole is fastened to the coupling device, so that the coupling device is fixed to the output shaft.

In the present invention (robot, power transmission device, power transmission system) configured as described above, the first rotation portion in which the third insertion hole into which the output shaft of the motor can be fitted is opened, and the second rotation in which the protruding shaft projects. And a transmission unit that transmits the rotation of the first rotation unit to the second rotation unit. Any one of the output shaft of the motor and the projecting shaft of the second rotating portion can be selectively fastened to a coupling device fastened to the screw shaft of the ball screw.

That is, this coupling device is provided with a first insertion hole that opens to one side in the thrust direction and a second insertion hole that opens to the other side in the thrust direction, and a screw shaft of a ball screw that is fitted into the first insertion hole. To be concluded. A third insertion hole that faces one side in the thrust direction when the output shaft and the screw shaft arranged toward the other side in the thrust direction are arranged on different axes (that is, arranged in parallel). The output shaft fitted into the first rotation portion is fastened to the first rotation portion, so that the output shaft is fixed to the first rotation portion, and the protruding shaft fitted into the second insertion hole is coupled to face one side in the thrust direction. The coupling device is fixed to the second rotating portion by being fastened to the device. Thereby, the rotation of the output shaft of the motor can be transmitted to the screw shaft of the ball screw in a parallel manner. The output shaft fitted into the second insertion hole when the power transmission device is removed from the output shaft and the coupling device, and the output shaft and the screw shaft are arranged on the same axis (that is, arranged in series). Is fastened to the coupling device, so that the coupling device is fixed to the output shaft. Thus, the rotation of the output shaft of the motor can be transmitted in series to the screw shaft of the ball screw. In this way, it is possible to easily switch the method for transmitting the rotation of the output shaft of the motor to the screw shaft of the ball screw between the series method and the parallel method.

In the present invention, the method of transmitting the rotation of the output shaft of the motor to the screw shaft of the ball screw can be easily switched between the series method and the parallel method.

The perspective view which shows the external appearance structure of the 1st state of the single axis robot which concerns on this invention. FIG. 2 is a partial cross-sectional view showing an internal configuration of the single-axis robot of FIG. 1. The fragmentary sectional view which expands and shows the periphery of a coupling unit. The fragmentary sectional view which expands and shows the periphery of a coupling unit. The front perspective view of a coupling unit. The rear perspective view of a coupling unit. The perspective view which shows the external appearance structure of the 2nd state of the single axis robot which concerns on this invention. FIG. 8 is a partial cross-sectional view showing an internal configuration of the single-axis robot of FIG. 7. The front perspective view which shows the external appearance structure of a power transmission device and a motor. The rear perspective view which shows the external appearance structure of a power transmission device and a motor. The rear perspective view which shows the external appearance structure of a power transmission device. The fragmentary sectional view which shows typically the structure of a power transmission device and a motor.

FIG. 1 is a perspective view showing an external configuration of a first state of a single-axis robot according to the present invention. FIG. 2 is a partial cross-sectional view showing the internal configuration of the single-axis robot of FIG. In the first state shown in FIGS. 1 and 2, the rotation of the output shaft 21 of the motor 2 is transmitted to the screw shaft 31 of the ball screw 3 in a series system (straight system).

The single-axis robot 1 includes a rectangular housing 11 that is long in the X direction, and a slider 13 that reciprocates in the X direction along the housing 11. Further, the single-axis robot 1 includes a motor 2 attached to the end of the housing 11 in the X direction, and the motor 2 generates a driving force for moving the slider 13.

That is, as shown in FIG. 2, the single-axis robot 1 includes a ball screw 3 and a coupling unit 4 that couples the ball screw 3 to the motor 2 inside the housing 11. The ball screw 3 includes a screw shaft 31 that is arranged parallel to the X direction and is rotatable, and a nut 32 that is screwed onto the screw shaft 31, and the slider 13 is attached to the nut 32. The motor 2 has a rotatable output shaft 21 disposed in parallel with the X direction. The screw shaft 31 of the ball screw 3 is coupled to the output shaft 21 of the motor 2 by the coupling unit 4. Therefore, when the motor 2 rotates the output shaft 21, the screw shaft 31 of the ball screw 3 rotates with the output shaft 21, and the nut 32 moves in the X direction with the slider 13.

3 and 4 are partial cross-sectional views showing the periphery of the coupling unit in an enlarged manner. FIG. 5 is a front perspective view of the coupling unit, and FIG. 6 is a rear perspective view of the coupling unit. 3 shows a state in which the output shaft 21 of the motor 2 and the screw shaft 31 of the ball screw 3 are coupled by the coupling unit 4. In FIG. 4, the configurations of the motor 2, the ball screw 3, and the coupling unit 4 are shown. Is shown exploded in the X direction, that is, in the thrust direction T of the output shaft 21 and the screw shaft 31. 3 and 4, the internal configuration of the motor 2 is indicated by a broken line, and the housing 11 partially shown in FIG. 3 is omitted in FIG. 4.

The motor 2 includes two radial bearings 22 that support the output shaft 21 from the radial direction R, an electric circuit (not shown) for rotating the output shaft 21, and a housing 23 that accommodates these radial bearings 22 and the like. . A shaft end 21a (output shaft end 21a) of the output shaft 21 protrudes from the housing 22 to one side Ta (that is, the screw shaft 31 side) in the thrust direction T. The shaft end 21a of the output shaft 21 has a cylindrical shape, and the outer peripheral surface of the shaft end 21a of the output shaft 21 is smoothly formed in parallel to the thrust direction T and has no step. The corner of the shaft end 21a is chamfered.

The screw shaft 31 of the ball screw 3 includes a screw portion 31a in which a screw thread 310 is provided and the nut 32 is screwed, and a shaft end 31b (screw shaft end 31b) provided adjacent to the screw portion 31a. A shaft end 31b extends from the screw portion 31a to the other side Tb in the thrust direction T (that is, the output shaft 21 side and the opposite side of the one side Ta). The shaft end 31b has a cylindrical shape, and the outer peripheral surface of the shaft end 31b of the screw shaft 31 is smoothly formed in parallel with the thrust direction T and has no step. The corner of the shaft end 31b is chamfered.

Then, the coupling unit 4 couples the shaft end 21a of the output shaft 21 and the shaft end 31b of the screw shaft 31 facing each other side by side in the thrust direction T. That is, the output shaft 21 and the screw shaft 31 arranged in series in the thrust direction T are coupled by the coupling unit 4 (series method). In other words, the output shaft 21 and the screw shaft 31 are arranged on the same axis A. ing. Here, the axis A is a virtual straight line parallel to the thrust direction T. The coupling unit 4 has a shaft 41 extending in the thrust direction T. The shaft 41 is a rigid body made of metal or the like, and has a rotationally symmetric shape with respect to an axis of symmetry parallel to the thrust direction T. The shaft 41 has a flange 411 formed at an end portion on one side Ta in the thrust direction T and a screw portion 412 formed at an end portion on the other side Tb in the thrust direction T. The shaft 41 is formed with a hollow portion 42 penetrating in the thrust direction T. The hollow portion 42 includes a first insertion hole 421 that opens to one side Ta in the thrust direction T and the other side in the thrust direction T. And a second insertion hole 422 that opens to Tb. Each of the first insertion hole 421 and the second insertion hole 422 has a concentric cylindrical shape extending in the thrust direction T, and the space between the first insertion hole 421 and the second insertion hole 422 is between the shaft 41 and the shaft 41. An annular protrusion 423 that protrudes inward from the inner wall of the hollow portion 42 is formed.

The first insertion hole 421 has a shape corresponding to the shape of the shaft end 31 b (first shaft end) of the screw shaft 31. In this example, the first insertion hole 421 is provided on the shaft end 31 b of the screw shaft 31. It has a cylindrical shape with a diameter equal to the diameter of the cylindrical shape. That is, the inner diameter of the first insertion hole 421 is equal to the outer diameter of the shaft end 31 b of the screw shaft 31. Therefore, the shaft end 31 b of the screw shaft 31 can be fitted into the first insertion hole 421 of the shaft 41 from the one side Ta in the thrust direction T without any play, and the shaft 41 is a screw fitted into the first insertion hole 421. The shaft end 31b of the shaft 31 is restrained in the radial direction R.

The second insertion hole 422 has a shape corresponding to the shape of the shaft end 21 a (second shaft end) of the output shaft 21, and in this example, the second insertion hole 422 has the shaft end 21 a of the output shaft 21. It has a cylindrical shape with a diameter equal to the diameter of the cylindrical shape. That is, the inner diameter of the second insertion hole 422 is equal to the outer diameter of the shaft end 21 a of the output shaft 21. Therefore, the shaft end 21a of the output shaft 21 can be fitted into the second fitting hole 422 of the shaft 41 from the other side Tb in the thrust direction T without any play, and the shaft 41 is fitted into the second fitting hole 422. The shaft end 21a of the shaft 21 is restrained in the radial direction R.

That is, the screw shaft 31 whose shaft end 31 b is fitted in the first insertion hole 421 and the output shaft 21 whose shaft end 21 a is fitted in the second insertion hole 422 are both in the radial direction R by the shaft 41. Be bound. As described above, the shaft 41 positions the shaft end 31b of the screw shaft 31 and the shaft end 21a of the output shaft 21 with each other in the radial direction R in a state in which the respective center lines coincide with each other.

The hollow portion 42 of the shaft 41 has a tapered hole 424 extending from the first insertion hole 421 to one side Ta in the thrust direction T. The taper hole 424 has a truncated cone shape whose diameter increases toward the one side Ta in the thrust direction T. The taper hole 424 includes a shaft end 31 b of the screw shaft 31 fitted in the first insertion hole 421, and the taper hole 424. A gap 425 is formed between the inner wall of the shaft 41 to be defined.

And the coupling unit 4 has a sparing 43 inserted into the gap 425. The sparing 43 has a rotationally symmetric shape with respect to an axis of symmetry parallel to the thrust direction T. A hollow portion 431 penetrating in the thrust direction T is formed in the sparing 43. The hollow portion 431 has a cylindrical shape having a diameter equal to the cylindrical shape of the shaft end 31 b of the screw shaft 31, and the shaft end 31 b of the screw shaft 31 is fitted into the hollow portion 431 of the sparing 43. On the other hand, the end of the other side Tb of the sparing 43 has a frustoconical outer shape whose diameter decreases toward the other side Tb in the thrust direction T. That is, the peripheral edge portion of the end portion on the other side Tb of the sparing 43 has a wedge shape, and functions as an insertion portion 432 (wedge) that can be inserted into and removed from the gap 425. Further, the sparing 43 has a flange 433 at the end of one side Ta.

When the insertion portion 432 of the sparing 43 is inserted into the gap 425 between the screw shaft 31 and the shaft 41, it is pressed against each of the inner wall of the tapered hole 424 of the shaft 41 and the outer periphery of the shaft end 31 b of the screw shaft 31. Is done. As a result, the shaft end 31 b of the screw shaft 31 fitted in the first insertion hole 421 is fastened to the shaft 41. Further, the flange 433 of the sparing 43 is fastened to the flange 411 of the shaft 41 by a screw 434. Thus, the screw shaft 31 can be firmly fixed to the shaft 41 by the sparing 43.

Incidentally, an O-ring 44 made of rubber is disposed inside the first insertion hole 421 of the shaft 41, and the shaft end 31 b of the screw shaft 31 is connected to the annular protrusion 423 of the shaft 41 via the O-ring 44. It is hit by. Therefore, the O-ring 44 is elastically deformed as the shaft end 31b of the screw shaft 31 is drawn into the first insertion hole 421 as the sparging 43 is inserted. Thus, the movement of the shaft end 31b of the screw shaft 31 is not hindered by passing through the O-ring 44, and the fastening strength between the shaft end 31b of the screw shaft 31 and the shaft 41 is improved. ing.

Further, the coupling unit 4 has a split fastening mechanism 45 provided on the other side Tb of the shaft 41. The cleaving mechanism 45 is formed integrally with the shaft 41 and is provided at the end of the other side Tb of the shaft 41. As shown in FIG. 5, the cleaving mechanism 45 includes two semicircular members 451, screws 452 that fasten the two semicircular members 451, and pins that attach the two semicircular members 451 to each other. 453. These two semicircular members 451 are arranged so as to form a circle, and a hollow portion 454 is formed between them. The hollow portion 454 of the cleaving mechanism 45 has a substantially cylindrical shape penetrating in the thrust direction T, and is aligned with the second insertion hole 422 of the shaft 41 in the thrust direction T. When the screw 452 is screwed in a state in which the shaft end 21a of the output shaft 21 is fitted into the second insertion hole 422 via the hollow portion 454 of the split tightening mechanism 45, the inner circumference of each semicircular member 451 becomes the output shaft 21. Is pressed against the outer periphery of the shaft end 21a (clamping). Thus, the two semicircular members 451 sandwich the shaft end 21 a of the output shaft 21, whereby the shaft end 21 a of the output shaft 21 is fastened to the shaft 41. Thereby, the output shaft 21 can be firmly fixed to the shaft 41 by the split tightening mechanism 45.

In this way, the screw shaft 31 of the ball screw 3 and the output shaft 21 of the motor 2 positioned in the radial direction R by the shaft 41 are fixed to the shaft 41 by the sparing 43 and the splitting mechanism 45, respectively. As a result, the screw shaft 31 of the ball screw 3 and the output shaft 21 of the motor 2 are coupled.

Furthermore, the coupling unit 4 has two thrust bearings 46 that support the shaft 41 in the thrust direction T, and a base 47 that supports the thrust bearing 46. The thrust bearing 46 has a housing washer 461 fixed to the base 47 and an axial washer 462 that supports the shaft 41. The base 47 is fixed to the housing 11 of the single-axis robot 1 by screws 470 and functions to support the shaft 41 with respect to the housing 11 via the thrust bearing 46.

Specifically, a shaft hole 471 penetrating in the thrust direction T is formed in the base 47. The diameter of the shaft hole 471 is slightly larger than the diameter of the outer periphery 41 a of the shaft 41 (the outer periphery of the cylindrical portion 41 b between the flange 411 and the screw portion 412), and the shaft 41 fits into the shaft hole 471 of the base 47. Further, the outer periphery 41 a of the cylindrical portion 41 b of the shaft 41 has a shape corresponding to the inner periphery of the axial washer 462 of each thrust bearing 46. That is, the outer circumference 41 a of the cylindrical portion 41 b of the sparing 43 is formed to have a diameter equal to the inner circumference of the axial raceway 462 of each thrust bearing 46, and the shaft 41 fits inside each thrust bearing 46. . The diameter of the housing washer 461 of each thrust bearing 46 is equal to or slightly larger than the diameter of the outer periphery 41a of the cylindrical portion 41b of the sparing 43. The two thrust bearings 46 are arranged so as to sandwich the peripheral edge portion 472 of the shaft hole 471 of the base 47 from the thrust direction T. A nut 481 is attached to the screw portion 412 of the shaft 41 with a washer 482 (chrysanthemum) sandwiched between the two thrust bearings 46 and the thrust bearing 46 on the other side Tb.

In this way, the washer 482, the thrust bearing 46, the peripheral edge 472 of the base 47, and the thrust bearing 46 arranged in the thrust direction T are sandwiched between the flange 411 and the nut 481. Therefore, when the nut 481 is screwed into the screw portion 412 of the shaft 41, the housing washer 461 of each thrust bearing 46 is pressed against the peripheral portion 472 of the base 47, and the shaft washer 462 of the thrust bearing 46 on the one side Ta is The shaft washer 462 of the thrust bearing 46 on the other side Tb is pressed through a washer 482 to a nut 481 that is screwed into the shaft 41. As a result, the housing washer 461 of each thrust bearing 46 is fixed to the base 47, and the axial washer 462 of the thrust bearing 46 is fixed to the shaft 41.

In such a configuration, the support in the thrust direction T of the screw shaft 31 and the output shaft 21 coupled by the coupling unit 4 is mainly realized by the thrust bearing 46. Further, the support in the radial direction R of the screw shaft 31 and the output shaft 21 is mainly realized by the radial bearing 22 of the motor 2.

FIG. 7 is a perspective view showing an external configuration of the second state of the single-axis robot according to the present invention. FIG. 8 is a partial cross-sectional view showing the internal configuration of the single-axis robot of FIG. In the second state shown in FIGS. 7 and 8, the rotation of the output shaft 21 of the motor 2 is transmitted to the screw shaft 31 of the ball screw 3 in a parallel manner (folding manner). In the following description, the difference from the first state will be mainly described, and portions common to the first state will be denoted by corresponding reference numerals and description thereof will be omitted. In this second state, the output shaft 21 of the motor 2 protruding toward the other side Tb in the thrust direction T and the screw shaft 31 of the ball screw 3 are arranged in parallel with each other, in other words, the output shaft 21 and the screw shaft 31 are disposed on different axes Aa and Ab. Here, the axes Aa and Ab are virtual straight lines parallel to the thrust direction T, respectively. The single-axis robot 1 includes a power transmission device 5 that transmits the rotation of the output shaft 21 to the screw shaft 31.

FIG. 9 is a front perspective view showing the external configuration of the power transmission device and the motor. FIG. 10 is a rear perspective view showing the external configuration of the power transmission device and the motor. FIG. 11 is a rear perspective view showing an external configuration of the power transmission device. FIG. 12 is a partial cross-sectional view schematically showing the configuration of the power transmission device and the motor. In FIG. 12, a part of the coupling unit 4 (around the second insertion hole 422) is schematically illustrated.

The power transmission device 5 includes a first rotating part 51 attached to the output shaft 21 of the motor 2, a second rotating part 53 attached to the screw shaft 31 of the ball screw 3, and the first rotating part 51 and the second rotating part 53. And a belt 55 wound around. Furthermore, the power transmission device 5 includes a housing 57 that rotatably supports the first rotating portion 51 and the second rotating portion 53. The housing 57 includes a first support portion 571 that supports the first rotating portion 51, a second support portion 572 that supports the second rotating portion 53, and a first support portion 571 and a second support portion 572. And a plate 573 to be fixed.

The first rotating unit 51 includes a pulley 511 and a rotating shaft 512 (first rotating shaft) fixed to the pulley 511. The rotation shaft 512 is provided so as to protrude from the center of the pulley 511 toward the one side Ta in the thrust direction T. The rotation shaft 512 and the pulley 511 can rotate around the same center line parallel to the thrust direction T. On the other hand, two radial bearings 581 are mounted in the thrust direction T inside the first support portion 571, and the rotating shaft 512 is supported in the radial direction R by these radial bearings 581. Specifically, the inner diameter of the inner ring of each radial bearing 581 is equal to the outer diameter of the rotating shaft 512, the rotating shaft 512 is fitted and attached to the inner ring of each radial bearing 581, and the outer ring of each radial bearing 581 is the first. It is attached to the support portion 571.

Also, the rotation shaft 512 is provided with a fitting hole 513 in the thrust direction T that opens to one side Ta in the thrust direction T. The insertion hole 513 has a cylindrical shape with a diameter equal to the cylindrical shape of the shaft end 21 a of the output shaft 21. That is, the inner diameter of the fitting hole 513 is equal to the outer diameter of the shaft end 21 a of the output shaft 21. Therefore, the shaft end 21 a of the output shaft 21 can be fitted into the fitting hole 513 of the rotating shaft 512 without play from the one side Ta in the thrust direction T, and the shaft end 21 a of the output shaft 21 fitted in the fitting hole 513. The rotating shaft 512 is positioned relative to each other in the radial direction R in a state where the respective center lines coincide with each other.

The power transmission device 5 has a cleaving mechanism 52 provided on one side Ta of the rotating shaft 512. The cleaving mechanism 52 is formed integrally with the rotating shaft 512 and thus provided at the end portion of the one side Ta of the rotating shaft 512. As shown in FIG. 11, the cleaving mechanism 52 includes an annular member 521 that is partially cut away, and a screw 522 that changes the width of the gap between the cutouts of the annular member 521. A hollow portion 523 is formed inside the annular member 521. The hollow portion 523 of the cleaving mechanism 52 has a substantially cylindrical shape penetrating in the thrust direction T, and is aligned with the insertion hole 513 of the rotating shaft 512 in the thrust direction T. When the screw 522 is screwed in a state where the shaft end 21 a of the output shaft 21 is fitted in the fitting hole 513 through the hollow portion 523 of the split-off mechanism 52, the inner periphery of the annular member 521 is the shaft end 21 a of the output shaft 21. Is pressed against the outer periphery of the plate (clamping). Thus, the annular member 521 sandwiches the shaft end 21 a of the output shaft 21, so that the shaft end 21 a of the output shaft 21 is fastened to the rotating shaft 512. As a result, the output shaft 21 can be firmly fixed to the rotating shaft 512 by the splitting mechanism 52.

The second rotating unit 53 includes a pulley 531 and a rotating shaft 532 (second rotating shaft) fixed to the pulley 531. The rotation shaft 532 protrudes from the center of the pulley 531 to one side Ta in the thrust direction T. The rotation shaft 532 and the pulley 531 can rotate around the same center line parallel to the thrust direction T and are concentric. It has the shape of On the other hand, two radial bearings 582 are attached in the thrust direction T inside the second support portion 572, and the rotating shaft 532 is supported in the radial direction R by these radial bearings 582. Specifically, the inner diameter of the inner ring of the radial bearing 582 is equal to the outer diameter of the rotating shaft 532, the rotating shaft 532 is fitted and attached to the inner ring of each radial bearing 582, and the outer ring of each radial bearing 582 is supported by the second ring. It is attached to the part 572.

The rotating shaft 532 has a protruding end 532a that protrudes from the second support portion 572 to the one side Ta in the thrust direction T. The rotating shaft 532 has a cylindrical shape with a diameter equal to the cylindrical diameter of the shaft end 21 a of the output shaft 21. That is, the outer diameter of the rotating shaft 532 is equal to the outer diameter of the shaft end 21 a of the output shaft 21. Therefore, instead of the shaft end 21 a of the output shaft 21 of the motor 2, the protruding end 532 a of the rotating shaft 532 can be fastened to the coupling unit 4.

That is, the protruding end 532a of the rotating shaft 532 has a shape corresponding to the shape of the second insertion hole 422. In this example, the protruding end 532a has a diameter equal to the diameter of the cylindrical shape of the second insertion hole 422. It has a cylindrical shape. That is, the outer diameter of the protruding end 532a is equal to the inner diameter of the second insertion hole 422. Therefore, the protruding end 532a of the rotating shaft 532 can be fitted into the second fitting hole 422 of the shaft 41 from the other side Tb in the thrust direction T without any play, and the shaft 41 is fitted into the second fitting hole 422. The protruding end 532a of the shaft 532 is restrained in the radial direction R.

When the screw 452 is screwed in a state where the protruding end 532a of the rotating shaft 532 is fitted into the second fitting hole 422 via the splitting mechanism 45 of the splitting mechanism 45, the inner circumference of each semicircular member 451 becomes the rotating shaft. It is pressed against the outer periphery of the protruding end 532a of 532 (clamping). Thereby, the rotary shaft 532 can be firmly fixed to the shaft 41 by the split tightening mechanism 45.

Further, the endless belt 55 is stretched over the pulley 511 of the first rotating part 51 and the pulley 531 of the second rotating part 53, and the rotation of the first rotating part 51 is transmitted to the second rotating part 53. The tension of the belt 55 is adjusted in advance when the power transmission device 5 is manufactured and shipped. For example, this tension adjustment can be performed by changing the position where the first support portion 571 and the second support portion 572 are attached to the plate 573 and adjusting the distance between the pulley 511 and the pulley 531.

Thus, the power transmission device 5 couples the output shaft 21 of the motor 2 and the screw shaft 31 of the ball screw 3 arranged in parallel. The power transmission device 5 transmits the rotation of the output shaft 21 of the motor 2 to the screw shaft 31 of the ball screw 3. That is, when the first rotating part 51 of the power transmission device 5 rotates with the rotation of the output shaft 21 of the motor 2, the belt 55 rotates with the first rotating part 51 and rotates the second rotating part 53. . As a result, the screw shaft 31 of the ball screw 3 fastened to the second rotating portion 53 rotates.

As described above, in the power transmission device 5 of the present embodiment, the first rotating part 51 in which the fitting hole 513 into which the output shaft 21 of the motor 2 can be fitted opens, and the second rotating part 53 in which the rotating shaft 532 protrudes. And a belt 55 that transmits the rotation of the first rotating unit 51 to the second rotating unit 53. Any one of the output shaft 21 of the motor 2 and the rotating shaft 532 of the power transmission device 5 can be selectively fastened to the coupling unit 4 fastened to the screw shaft 31 of the ball screw 3.

That is, this coupling unit 4 is provided with a first insertion hole 421 that opens to one side Ta in the thrust direction T and a second insertion hole 422 that opens to the other side Tb in the thrust direction T. It is fastened to the screw shaft 31 of the ball screw 3 fitted in 421. Then, in a state where the output shaft 21 arranged toward the other side Tb in the thrust direction T and the ball screw 3 are arranged in parallel, the output shaft 21 fitted in the fitting hole 513 facing the one side Ta in the thrust direction T. Is fastened to the first rotating portion 51, whereby the output shaft 21 is fixed to the first rotating portion 51. Further, the coupling unit 4 is fixed to the second rotating portion 53 by fastening the rotating shaft 532 fitted in the second fitting hole 422 so as to face the one side Ta in the thrust direction T. Thereby, the rotation of the output shaft 21 of the motor 2 can be transmitted to the screw shaft 31 of the ball screw 3 in a parallel manner (first state). Further, in a state where the power transmission device 5 is detached from each of the output shaft 21 and the coupling unit 4 and the output shaft 21 and the screw shaft 31 are arranged in series, the output shaft 21 fitted in the second insertion hole 422 is provided. The coupling unit 4 is fixed to the output shaft 21 by being fastened to the coupling unit 4. Thereby, the rotation of the output shaft 21 of the motor 2 can be transmitted to the screw shaft 31 of the ball screw 3 in a series manner (second state). In this way, the method of transmitting the rotation of the output shaft 21 of the motor 2 to the screw shaft 31 of the ball screw 3 can be easily switched between the serial method (first state) and the parallel method (second state). Yes.

At this time, power is transmitted from the first rotating portion 51 to the second rotating portion 53 by the endless belt 55 that is stretched between the first rotating portion 51 and the second rotating portion 53. In particular, in this embodiment, the 1st rotation part 51, the 2nd rotation part 53, and the belt 55 are assembled as one power transmission device 5, and are unitized. Therefore, if the power transmission device 5 is assembled with the tension of the belt 55 adjusted at the time of production of the power transmission device 5, it is necessary to readjust the tension of the belt 55 when switching from the serial system to the parallel system thereafter. No.

Further, the power transmission device 5 includes a radial bearing 581 that supports the first rotating portion 51 in the radial direction R. As a result, the first rotating portion 51 can be firmly supported in the radial direction R.

Further, the power transmission device 5 includes a radial bearing 581 that supports the second rotating portion 53 in the radial direction R. As a result, the second rotating portion 53 can be firmly supported in the radial direction R.

Thus, in the above embodiment, the single-axis robot 1 corresponds to an example of the “robot” of the present invention, and the power transmission system 6 (FIG. 8) composed of the coupling unit 4 and the power transmission device 5 is the main robot. The power transmission device 5 corresponds to an example of the “power transmission device” of the present invention, and the first rotating portion 51 corresponds to an example of the “first rotating portion” of the present invention. The insertion hole 513 corresponds to an example of the “insertion hole” of the present invention, the second rotation part 53 corresponds to an example of the “second rotation part” of the present invention, and the rotation shaft 532 corresponds to the “protrusion” of the present invention. The belt 55 corresponds to an example of “transmission part” and “belt” of the present invention, the ball screw 3 corresponds to an example of “ball screw” of the present invention, and the screw shaft 31 corresponds to an example of “shaft”. It corresponds to an example of “screw shaft”, and the nut 32 and the slider 13 cooperate. The coupling unit 4 corresponds to an example of the “coupling device” of the present invention, and the first insertion hole 421 corresponds to an example of the “first insertion hole” of the present invention. The second insertion hole 422 corresponds to an example of the “second insertion hole” of the present invention, the motor 2 corresponds to an example of the “motor” of the present invention, and the output shaft 21 corresponds to the “output shaft” of the present invention. The radial bearing 581 corresponds to an example of the “first radial bearing” of the present invention, the radial bearing 582 corresponds to an example of the “second radial bearing” of the present invention, and the axis Aa and the axis Ab are The invention corresponds to an example of “different axes” of the invention, and the axis A corresponds to an example of “same axis” of the invention.

Note that the present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the coupling unit 4 and the power transmission device 5 described above may be used to transmit the rotation of the output shaft 21 of the motor 2 to the screw shaft 31 of the ball screw 3 in a multi-axis robot other than the single-axis robot 1. good.

Further, the specific mechanism for fastening the shaft end 21a of the output shaft 21 to the first rotating portion 51 is not limited to the split fastening mechanism 52, and may be another mechanism such as sparing.

Further, the specific mechanism for fixing the screw shaft 31 to the shaft 41 is not limited to the sparing 43, but may be another mechanism such as a split tightening mechanism.

Further, the specific mechanism for fixing the output shaft 21 to the shaft 41 is not limited to the cleaving mechanism 45 but may be other mechanisms such as sparing.

Further, the configuration for transmitting the rotation of the first rotating unit 51 to the second rotating unit 53 is not limited to the belt 55, and may be another mechanism such as a gear.

The specific configuration of the coupling device that is fastened to the screw shaft 31 of the ball screw 3 and that is selectively fastened to the output shaft 21 of the motor 2 or the rotating shaft 532 of the power transmission device 5 is the above-described coupling unit. It is not limited to four. Therefore, for example, the coupling device may be configured by a leaf spring coupling or the like.

As described above with reference to specific examples, for example, various modifications shown below can be added as appropriate to the present invention.

That is, the robot may be configured so that the transmission unit is an endless belt that is stretched between the first rotating unit and the second rotating unit. In particular, in the present invention, the first rotating part, the second rotating part, and the belt are assembled as one power transmission device. Therefore, if the power transmission device is assembled with the belt tension adjusted during production of the power transmission device, there is no need to readjust the belt tension when switching from the serial system to the parallel system thereafter.

Further, the power transmission device may be configured such that the robot has a first radial bearing that supports the first rotating portion in the radial direction. Thereby, the first rotating part can be firmly supported in the radial direction.

Further, the power transmission device may be configured such that the robot has a second radial bearing that supports the second rotating portion in the radial direction. Thereby, the second rotating part can be firmly supported in the radial direction.

This invention can be applied to all techniques for transmitting the rotation of the output shaft of a motor to the screw shaft of a ball screw.

DESCRIPTION OF SYMBOLS 1 ... Single-axis robot (robot), 13 ... Slider (moving body), 2 ... Motor, 21 ... Output shaft, 3 ... Ball screw, 31 ... Screw shaft, 32 ... Nut (moving body) 4 ... Coupling unit (coupling device) , 421 ... 1st insertion hole, 422 ... 2nd insertion hole, 51 ... 1st rotation part, 513 ... Insertion hole (3rd insertion hole), 53 ... 2nd rotation part, 532 ... Rotation shaft (protrusion shaft), 55 ... Belt (transmission part), 581 ... Radial bearing (first radial bearing), 582 ... Radial bearing (second radial bearing), 5 ... Power transmission device, 6 ... Power transmission system, T ... Thrust direction, R ... Radial Direction, A ... Same axis, Aa, Ab ... Different axes

Claims

A ball screw having a rotatable screw shaft;
A moving body that is screwed to the screw shaft and moves with the rotation of the screw shaft;
A first fitting hole that opens to one side in the thrust direction, and a second fitting hole that opens to the other side in the thrust direction, and a coupling device fastened to the screw shaft that is fitted into the first fitting hole; ,
A motor having a rotatable output shaft and rotating the output shaft;
A first rotating part having a third insertion hole into which the output shaft can be fitted, a second rotating part having a projecting shaft capable of being fitted into the second fitting hole, and rotation of the first rotating part to the second A power transmission device having a transmission part for transmitting to the rotating part,
In a state where the output shaft arranged toward the other side in the thrust direction and the screw shaft are arranged on different axes, the output shaft fitted into the third insertion hole facing one side in the thrust direction is It is fixed to the first rotating part by being fastened to the first rotating part, and the protruding shaft is fitted into the second fitting hole so as to face one side in the thrust direction and fastened to the coupling device. And while the coupling device is fixed to the second rotating part,
In a state where the power transmission device is detached from the output shaft and the coupling device and the output shaft of the motor and the screw shaft are arranged on the same axis, the output shaft is fitted into the second insertion hole, and A robot in which the coupling device is fixed to the output shaft by being fastened to the coupling device.
The robot according to claim 1, wherein the transmission unit is an endless belt that is stretched between the first rotating unit and the second rotating unit.
The robot according to claim 1 or 2, wherein the power transmission device includes a first radial bearing that supports the first rotating portion in a radial direction.
The robot according to any one of claims 1 to 3, wherein the power transmission device includes a second radial bearing that supports the second rotating portion in a radial direction.
A first rotating part having a third insertion hole into which an output shaft of the motor can be fitted;
A first insertion hole that opens to one side in the thrust direction and a second insertion hole that opens to the other side in the thrust direction are provided, and are fastened to a screw shaft of a ball screw fitted in the first insertion hole, A second rotating part having a projecting shaft that can be fitted in the second fitting hole of the coupling device that is arranged on the same axis as the screw shaft and can be fastened to the output shaft fitted in the second fitting hole;
A transmission unit that transmits the rotation of the first rotation unit to the second rotation unit;
In a state where the output shaft arranged toward the other side in the thrust direction and the screw shaft are arranged on different axes, the output shaft fitted into the third insertion hole facing one side in the thrust direction is In addition to being fixed to the first rotating part by being fastened to the first rotating part, the protruding shaft is fitted into the second insertion hole of the coupling device and fastened to one side in the thrust direction. Thus, the power transmission device in which the coupling device is fixed to the second rotating portion.
A coupling device provided with a first insertion hole that opens to one side in the thrust direction and a second insertion hole that opens to the other side in the thrust direction, and that can be fastened to a screw shaft of a ball screw that is fitted into the first insertion hole When,
A first rotating part having a third insertion hole into which an output shaft of the motor can be fitted, a second rotating part from which a projecting shaft capable of being fitted into the second fitting hole projects, and the rotation of the first rotating part. A power transmission device having a transmission portion for transmitting to the second rotating portion,
In a state where the output shaft arranged toward the other side in the thrust direction and the screw shaft are arranged on different axes, the output shaft fitted into the third insertion hole facing one side in the thrust direction is The output shaft is fixed to the first rotating portion by being fastened to the first rotating portion, and the protruding shaft fitted in the second insertion hole facing one side in the thrust direction is the coupling device. The coupling device is fixed to the second rotating part by being fastened to
In a state where the power transmission device is detached from the output shaft and the coupling device, and the output shaft of the motor and the screw shaft are arranged on the same axis, the output shaft fitted into the second insertion hole is A power transmission system in which the coupling device is fixed to the output shaft by being fastened to the coupling device.